more automatic tests for containers

[Kazu Yamamoto ( 山本和彦 )]

> I definitely prefer the "==" form for stating laws the interface
> follows.
> 
> Doctest came from the Python tradition, which is a very imperative
> outlook on life. I wonder whether doctest could be modified to better
> match the programming, documentation, and testing style of Haskell. In
> particular, I'd expect it to recognize "=="-style statements as things
> to test. 

Please read:

	http://www.haskell.org/pipermail/libraries/2011-December/017382.html

> The only real issue is whether those statements should be
> considered unit tests or properties (testable by QuickCheck and
> SmallCheck), since those two categories have very different methods of
> being verified.

I agree.

P.S.

I have extended test-framework-th to handle doctest (HUnit) also. I
will probably release this in this week.

--Kazu